The present invention relates to a method for determining a closed trajectory by means of a laser and a laser light sensor as well as an apparatus for determining a closed trajectory.
Methods and apparatuses of the kind mentioned in the introduction are used, in particular, for methods of measurement that are intended to determine the position of a rectilinear reference direction or reference axis relative to the position of the center axis or axis of symmetry of a circular cylindrical bore or opening of a body or of an apparatus in order to bring this bore or opening into alignment with another bore, for example, the center axis of which then represents the reference axis. For this, the laser is aligned such that the laser light beam of the laser can be aligned coincidentally with the reference axis. Furthermore, the laser light sensor is arranged in a defined position in the bore and a flat field of view of the laser light sensor is arranged perpendicularly to the center axis of the bore and the origin of the coordinate system of the field of view is arranged, at least approximatively, in the center of the bore. While this arrangement of the field of view is maintained, the field of view is brought or rotated into various mutually inclined angular positions, with the field of view being irradiated by the laser light beam in each angular position. When a misalignment is then present, that is, when the reference axis is not aligned with the center axis, the coordinates of the laser light spot of the laser light beam recorded in any angular position of the field of view generally describe a closed curved trajectory curve in the form of an ellipse or a circle, insofar as an angular range of 360 degrees is covered in total by the adjusted angular positions. The center of the circle or the ellipse then lies on the center axis and, on the basis of the creation of the circle or ellipse, it is then possible to determine the alignment of a reference axis relative to a center axis of a cylindrical bore.
The measurement of the angular position or the inclination angle of the fields of view generally resorts to an angle measurement instrument, such as an inclinometer, which enables the measurement of an inclination relative to the direction of gravitational force. The measurement of the angular position serves for determination of the angular position of the respective trajectory curve described by the laser light point and functions with high accuracy when the bores of turbines, for example, are to be aligned, which are essentially horizontally aligned. For the determination of the alignment of essentially vertically aligned bores or openings, it is not possible—owing to the principle of measurement—to use an inclinometer or else not possible to use it with sufficient accuracy. This is correspondingly also the case for unstable floors, that is, when the bore is situated on a ship, for example.
Methods and apparatuses that operate with laser light sensors having flat fields of view and/or having angle measurement instruments or inclinometers are generally known, for example, from DE 195 06 471 A1, DE 102 36 555 A1, DE 101 42 462 A1, DE 101 38 831 A1, DE 39 11 307 A1, DE 199 49 834 A1, DE 10 2004 024 398 A1, and DE 11 2004 000 113 T5.